Self-cleaning anchor



Oct. 10, 1939. F E, O'NElLL 2,175,540

SELF-CLEANING ANCHOR Filed Aug. 16, 1937 57 INI/Nm? f/eAA/K al1/Ha ATTORNEY Patented Oct. 10, 1939v 2,175,540 SELF-CLEANING ANCHOR Frank E. ONeill, Glendale, Calif., assignor to Mordica O. Johnston, Glendale, Calif.

Application August 16, 1937, SeriallNo.l 159,342

4 Claims. (Cl. 16B-1) This invention relates to well equipment, especially the type used in oil well production work, and particularly pertains to a self-cleaning anchor.

In connection with various types of oil well equipment, pipe having perforated walls is lowered into the well. A commonly used structure of this kind is a perforated anchor which is lowered into the well below a packer for production or testing purposes. In many instances this anchor is lowered into an open hole of the well bore so that there is not only the possibility of clogging due to the perforations, but there is also a great probability that the formation will cave and that debris will fill the anchor perforations.

vIn some instances such a resulting condition is highly objectionable, such for example in connection with formation testing apparatus, and particularly formation testing apparatus which includes a pressure bomb for recording the fluid pressure existing in an area of a well bore which has been closed o at the bottom of the well by the use of a packer. When formation tests are made it is common to lower the testing device to thebottom of a well on'a drill string. This testing device includes a packer above which a valve is mounted to admitl and entrap fluid within the drill string. The packer is formed with a central passageway therethrough and a length of perforated pipe is carried beneath the packer and communicates with the central passageway. At a point within or below the perforated pipe a fluid pressure recording device is placed. In the event that the perforations become clogged fluid will not flow through the perforations and upwardly in the drill string, but pressure will be built up within the sealed area so that a false reading will be made by the pressure recordingdevice. It is the particular object ofthe present invention therefor to provide means whereby the perforations within a pipe submerged in the fluid of a well will be automatically cleaned in the event that an accumulation of dirt and debris tends to clog them.

The present invention contemplates the provision of valve means acting to relieve an excessive built up pressure within a sealed area of well bore and cooperating to hydraulically or mechanically clean the perforations if they are clogged.

The invention is illustrated by way of .example in the accompanying drawing in which:

Figure 1 is a view in vertical section and elevation showing a portion of a well testing tool seated within a well bore and disclosing one form of the present invention. f

Fig. 2 is a fragmentary view showing a form of relief valve suitable for use Ain carrying out the present invention.

Fig. 3 is a fragmentary view of another form of relief valve which may be used.

Fig. 4 is an enlarged view of the type of valve shown in Fig. 1.

Fig. 5 is a fragmentary view showing a fluid operated mechanical perforation cleaner.

Referring more particularly to the drawing, I0 indicates a well bore having a seat II against which a rathole packer I2 is seated. Disposed above the packer is a tubular body I3 of a well testing tool or of a drill string. It is understood that this particular structure is shown by way of example only in order to demonstrate the application and value of the present invention, and that various other applications of the invention might be made without departing from the spirit of the invention as claimed. Mounted beneath the packer I2 is a pipe I4 formed with perforations I5, the pipe being usually called a perforated anchor. A coupling I6 isrsecured at the lower end of the pipe I4 and receives the upper threaded end of a housing I1 within which a fluid pressurerecording device I9 is mounted.l It is understood that the fluid pressure recording device is shown diagrammatically since its construction is not essential to the present invention. Perforations I9 may be formed through the Wall of the housing II to permit the fluid within the well bore to gain access to the pressure responsive means of the fluid pressure recording device. As previously stated it sometimes occurs that due to the thickness of mud, silt, debris, and cavings occurring in the well bore, the perforations I5 of the pipe I4 may become clogged. It will be evident by reference to Fig. 1 that if this condition prevails the native uid pressure of the formation may be blocked since liquid will not flow to the testing tool and the fluid pressure will not be relieved. The result will be that the liqu'id sample obtained in the formation testing device will be small and will give an incorrect indication of the condition of the liquid and the pressure within the formation, while at the same time the fluid pressure measuring device will respond to an excessive pressure in the area below the packer and will give a false high pressure reading. In order to overcome this and like conditions various means are here shown. The structures shown in Figs, 1 and 4 provide for an opening 2|! through the partition wall of the coupling I6, the upper end of the opening forming a valve seat 2l to receive a valve element 22 here indicated as a ball.

This valve ball is coniined within a cage 23 and is yieldably held upon its seat by a spring 23 also within the cage. 'I'he cage 23 is here indicated as being threaded into lower end of the pipe I4. In this particular 'form of device it is contemplated that when the perforations I5 in the pipe I4 become completely clogged or partially obstructed so that an excessive pressure will build up within the coniined area of the well bore. this pressure will act through the relatively large opening I3 oi the housing I1 or through the supplemental pipe I1 to lift the valve ball 22 from its seat and establish circulation of flow of iiuid through the passageway 2li and the pipe I4 and upwardly into the drill string. This will equalize the pressure around the pipe I4 and within the pipe I4. under which conditions there would be a tendency for the accumulation of material which clog the perforations to become loosened and to pass from the perforations. If that occurs pressure acting to lift the valve bail 22 will be relieved immediately and the valve ball will seat since circulation of fluid will then take place -through the perforations I5 normally intended.

In the form of the invention shown in Fig. 2 a diiierent type of valve is provided. 'I'his valve comprises a plunger 25 slidably mounted within a valve sleeve 26. The valve lsleeve 26 is here shown as attached to the coupling I6 and to be in communication with the opening formed through the partition wall of the coupling. The valve plunger is ot the piston type and when acted upon by the iiuid pressure bearing against its lower face will move and uncover one or more Yperforations 21 formed through the wall of the sleeve 26. 'Ihis movement will be opposed by the spring 28 mounted within the sleeve. This spring may be adjustably set in position by a threaded thimble 29 mounted upon the upper end of the sleeve and making it possible for a different pressure to b e established before the valve plunger 25 begins to move. The perforations 21 in the sleeve are preferably arranged in progressive diameter from the lower end of the sleeve, thus as the valve plunger is forced to raise by fluid pressure thereby indicating an excessive fluid pressure, the plunger will successively uncover the perforations 21 until its pressure is relieved and equalized inside and outside of the pipe I4.

In the form oi' the invention shown in Fig. 3 of the drawing, a valve thimble 30 is provided to receive a plunger valve 3l carrying an outwardly extending pin 32. The pin 32 projects through the perforation 33 and is yields oly held in this position by a spring 34. When pressure becomes excessive in the well bore the pin 32 is forced inwardly and at the same time the plunger 3| uncovers relief slots 35, thereby increasing the area of opening through which the iluid may flow. When the pressure is relieved exteriorly oi the well bore the spring 34 will force the pin 32 outwardly and this will tend to clean the perforation 33 by mechanical movement. It is undertsood that in connection with this type of device a plurality of perforations in the pipe I4 may be equipped with these valves.

In the form of the invention shown in Fig. 5 of the drawing, a piston 36 is mounted within a cylinder 31. Fluid pressure is exerted against the piston through openings 38 in the cylinder which is of much larger area than the perforations to be cleaned, and they piston is forced to rise by differential pressure against the response of a spring 39. Mounted on the piston is a rod 4l and pivotally mounted on the rod is a plurality o! knives 4I which act when the rod is moved upwardly te be forced outwardly through the side walls of the pipe I4 to open the perforations and to positively clean the accumulated material from them. A plurality of guide plates 42 are secured to the inner wall of pipe I4 contiguous to the openings Ii and' serve to guide the knives into and out of the perforations II. When the perforations have been opened the exterior pressure will have been relieved and the piston 36 will be restored. to its lowermost position by the action of the spring 3l. 'I'his will retract the blades 4I and leave the slots Ii clear. It will be seen that in the use of the present invention the devices provided act to establish equilibrium of iiuid through'the interior of the pipe whereby the accumulated material within the perforations will be disturbed and will tend to be dislodged. This insures that the perforations may be maintained clean at substantially all times, and it will further result that when the fstructure is used with a pressure bomb that a deiinite indication will be made in the pressure bomb reading to show the true condition within the test area.

While I have shown the preferred form of my invention, and means of practicing the same, it will be understood that various changes might be made in the construction of the devices used therewith, by those skilled in the art, without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A self cleaning anchor comprising a primary tubular section and a secondary tubular section, said secondary tubular section being substantially closed at its lower end, said sections having openings in their wall to permit uid to flow thereinto from a body of fluid within which said anchor is submerged, a coupling connecting between said sections and having an opening in a wall thereof, a rod element extending from said secondary section through said coupling opening and into said primary section, a piston connected to the lower end of said rod and operable within said secondary section, a plurality of knife members carried by the upper end of said rod element and adapted to move through the openings in said primary section to clean the same, and means responsive to a predetermined iiuid pressure for actuating said knife members.

2. A self cleaning anchor comprising a primary tubular section. a secondary tubular section closed at its lower end, a coupling member connecting between said primary and said secondary sections, the wall ofsaid primary section being formed with perforations whereby a fluid within which the sections are submerged may pass inwardly through the perforations and outwardly through the open end of saidA primary Section, the wall of said secondary section having openings through which the iiuid may pass into said section, walls providing an opening in said coupling, a rod adapted for reciprocation in said coupling opening and having portions extending within said primary and said secondary sections,

'a piston carried by said rod for movement in saidsperforagons.

means for withdrawing said knife members from said perforations.

3. A self cleaning anchor comprising a primary tubular section, a secondary tubular section closed at its lower end, a coupling member connecting between said primary and said secondary sections, the wall of said primary section being formed with perforations whereby a iluid within which the sections are submerged may pass inwardly through the periorations and outwardly through the open end of said primary section, the wall of said secondary section having openings through which the iiuid may pass into said section, walls providing an opening in said coupling, a rod adapted for reciprocatlon in said coupling opening and having portions extending within said primary and said secondary sections, a piston carried by said rod for movement in said secondary tubular section, a plurality oi knife members carried by said rod and adapted to move through the perforations in said primary section to clean the same, means for moving said knife members through said .periorations, means for withdrawing said knife members from said perforations, and means for guiding said knife members in their movement relative to 4. A self cleaning anchor comprising a primary tubular section, `a secondary tubular section closed at its lower end, a coupling member connecting between said primary, and secondary sections, the wall of said primary section being formed with perforations whereby a fluid within which the sections are submerged may pass inwardly through the periorations and outwardly through the open end of said primary section, the wall of said secondary section having openings through which the iiuid may pass into said section, walls providing an opening in said coupling, a rod adapted for reciprocation in said coupling opening and having portions extending within said primary and said secondary sections, a piston carried by said rod for movement in said secondary tubular section, a plurality of knife members carried by said rod and adapted to move through the periorations in said primary section to clean the same, means for moving said knife members through said perforations, and guide elements on said primary section acting to control the movement of said knife members relative to said perforations.

FRANKE. ONEILL. 

